1. Field of the Invention
The present invention relates to a method and system for contour fitting and posture identification that is on a nearly real-time basis.
2. Description of the Related Art
Due to the growth of the elderly population, the demand for elderly health-care and daily nursing care services will increase in the near future. However, the manpower growth in these services cannot keep pace with the elderly population growth. Thus, the human resources for health and nursing care will be very limited, and heavily disabled people, who require intensive care, will suffer the most under the scarce labor situation. Without enough medical resources, some nursing care issues such as pressure ulcer prevention management will become critical to the heavily disabled people. Therefore, developing an auxiliary system that can be used in medical facilities, for example the pressure ulcer prevention management, for the heavily disabled people becomes a very important research direction.
Pressure ulcers result from tissue death due to lack of oxygen supply. While remaining in the same posture for a long time, localized skin and tissue death may occur due to prolonged, irreversible ischemia brought by compression of soft tissue. In order to reduce the risk of pressure ulcer development, a medical attendant has to regularly change the position of a heavily disabled patient in bed for releasing compressed tissue from pressure.
In order to prevent patients from remaining in the same posture for an extended time, some posture monitor and alarm systems have been developed. U.S. Pat. No. 5,038,137 and U.S. Pat. No. 5,914,660 disclose a monitor and alarm system or apparatus using carry-on sensors. However, an individual will feel uncomfortable to carry the carry-on sensors all the time.
U.S. Pat. No. 5,184,112 discloses an apparatus for monitoring the position of a patient in bed, and U.S. Pat. No. 5,884,488 discloses an early warning bed egress alarm system. Both patents use pressure sensors to detect the position of a patient. The disclosed apparatus and system can detect only the patient's position, but cannot tell whether the patient has remained in a fixed posture for a long time.
U.S. Pat. No. 6,468,234 discloses a method and apparatus for measuring sleep quality that utilizes sensors incorporated in a sheet laid on top of a conventional mattress. The sensors can collect information such as the subject's position, body temperature, movement, mattress pressure, breathing and heart rate, as well as episodes of snoring and teeth grinding (bruxism). Nevertheless, the apparatus cannot identify body posture.
U.S. Pat. No. 6,791,460 discloses a patient position detection system having at least three different modes of operation. However, the system cannot detect the posture of a patient.
“Monitoring patient respiration and posture using human symbiosis system” by Nishida et al, Intelligent Robots and Systems, Proceedings of the 1997 IEEE/RSJ International Conference on IROS '97, Vol. 2, pp. 632-639, 1997, teaches a system having a microphone, CCD (Charge Coupled Device) and 221 force sensing resistors. The disclosed system applies a threshold level to sensor values generated by force sensing resistors, and determines body posture based on the distribution of the sensor values. However, the system may easily misjudge the posture and require more sensors.
“Body parts positions and posture estimation system based on pressure distribution image” by Harada et al, IEEE Proc. of International Conference on Robotics and Automation, Vol. 2, pp. 968-975, 1999, teaches a system that detects body position and posture using pressure distribution image analysis method. This system requires more sensors and consumes more system resources, and doesn't have a user adaptation mechanism.
“Infant Behavior Recognition System Based on Pressure Distribution Image” by Harada et al, Proceeding of the 2000 IEEE International Conference on Robotics and Automation, San Francisco, pp. 4082-4088, 2000, teaches a system for recognizing an infant's behavior. The system requires more sensors and is only applied to infants.
“Estimation of Bed-Ridden Human's Gross and Slight Movement Based on Pressure Sensors Distribution Bed” by Harada, ICRA 2002: 3795-3800, discloses a system that can identify the object in bed, which is an object or a human being, measure breathing rate and recognize lying postures, sit-up position or movement of arms. The system requires more sensors and consumes a lot of system resources, and furthermore, doesn't have a user adaptation mechanism.
In conclusion, present systems or apparatuses suffering from some deficiencies cannot meet the future requirement of elderly healthcare. Therefore, a new system without the above-mentioned deficiencies shall be developed.